[TUTORIAL] Hierarchical datasets with `TreeStore`

[FrancescAlted]

TreeStore is one of Python-Blosc2's headline features, and doc/reference/tree_store.rst documents its API. However, there is no interactive tutorial notebook in doc/tutorials/ showing how to use TreeStore to organize and query complex datasets.

Suggested Work

Create a new Jupyter Notebook at doc/tutorials/17.treestore-hierarchies.ipynb and register it in doc/tutorials/index.rst.

The notebook should demonstrate:

1. Container layouts: Creating and opening in-memory stores, single-file zip stores (.b2z), and directory layouts (.b2d).
2. Hierarchy & Groups: Creating groups and populating nested paths (e.g., /experiment/run_01/measurements, /metadata/config).
3. Storing mixed containers: Inserting blosc2.NDArray arrays, blosc2.CTable tables, and custom scalar/dictionary attributes (attrs).
4. Traversal & Discovery: Walking through trees with tree.walk() and searching for nodes matching specific criteria.
5. Updating nodes & compression: Replacing or appending nodes in existing stores.
6. Visualizing with b2view: Mentioning how the generated .b2z/.b2d file can be browsed in the terminal via b2view.